The present invention relates to a method for operating a processing machine, a control program for operating a processing machine, a control device for a processing machine, and a processing machine, all of which provide vibration compensation.
The following discussion of related art is provided to assist the reader in understanding the advantages of the invention, and is not to be construed as an admission that this related art is prior art to this invention.
Vibrations are a common occurrence during processing operations performed by machine tools, industrial robots, etc. Vibrations lead to processing inaccuracies. In many cases the processing inaccuracies can be tolerated. In other cases the processing inaccuracies cannot be tolerated. In particular the vibrations can in some cases even lead to such an extreme that the processing machine starts to chatter. In a situation of the kind operation must proceed for example at a lower feed rate, as a result of which productivity is reduced.
The forms of vibrations occurring can be different in nature depending on processing machine. In the case of a cantilever arm, for example, a typical flexural vibration (“trunk movement”) is a frequent occurrence. Linear or torsional vibrations are also possible.
The possibilities for damping vibrations are limited in the prior art. In traditional mechanical engineering, for example, passive vibration absorbers are used. Passive vibration absorbers are auxiliary masses which are resiliently mounted on the displaceable mechanical structure and tuned to the frequency that need to be damped.
It is also known in the prior art to employ active vibration dampers for damping vibrations of mechanical structures. With active vibration dampers, an absolute movement of the mechanical structure in space is determined by means of a corresponding system of sensors. The absolute movement is analyzed in order to determine a compensation movement for a compensating mass which damps the vibration of the mechanical structure. A compensating drive arranged on the mechanical structure and acting on the compensating mass is actuated in accordance with the determined compensation movement such that the compensating mass is displaced relative to the mechanical structure by means of the compensating drive in accordance with the compensation movement.
The approach typically adopted in the case of active vibration dampers cannot be applied without careful consideration in the case of mechanical structures which are displaced more or less continuously. In particular, the active vibration damper would counteract the desired reference displacement movement and therefore make the movement more difficult.
It would therefore be desirable and advantageous to obviate prior art shortcomings and to provide an improved approach for damping vibrations of displaceable mechanical structures with an active vibration damper.